A number of expensive and elaborate security systems are available to protect homes against unauthorized entry. A variety of sensors are used to detect the opening of a door or window or to detect motion within a dwelling and then activate an alarm, providing the alarm is activated. It is axiomatic that the system must accommodate the normal activities of the occupants of the home without sounding an alarm. This usually requires that the system be disarmed when entering the home and armed when leaving the home. It is also known to unlock or unlatch a door by remote control as by a radio link so that an authorized person having a properly coded radio transmitter can cause the door to unlatch by activating the transmitter when approaching the door. This avoids the inconvenience of finding the correct key and finding the keyhole which is difficult while carrying packages, for example, and also avoids a delay when a person might desire quick entry for security purposes. It is desirable to integrate a door opener and an intrusion detector into a single system since door entry and disarming the alarm are joint functions.
Generally, the available security systems are permanently installed in a home and cannot be readily removed. In many situations, particularly where the home is a rented apartment, the occupants desire to have a security system even though they may expect to live there for such a short time that the installation of a conventional security system is not economically justified. It is thus desirable to have a security system which can be readily installed and subsequently removed without permanent damage to the dwelling so that it may be reinstalled in another place.